Pump cylinder assembly



Feb. 19, 1957 J. ENTWISTLE PUMP CYLINDER ASSEMBLY Filed April 26, 1945 INVENTOR JAMES ENTWISTLE ATTORNEY United States Patent United States of America -as-represnted by-the United States Atomic Energy Commission Application April 26, 1945, Serial No. 590,435

3 Claims. (Cl.3093) This invention relates to a pump and particularly to a finely sealed pump of atype more particularly described in the copending application of Anthony A. Abbatiello, SerialNo. 590,433, filed April 26, 1945.

Pumps having floating pistons, by which is meant pistons which reciprocate within a cylinder but are out of contact therewith and which are sealed by means other than pressure rings, are known and have been described in the prior art. Many of such pumps are used for vacuum services or for other services in which considerable differential pressures exist on opposite sides of the sealing means. Normal methods of sealing, for instance by the use of a gasket, tightly clamped between the parts, do not give a sufliciently tight seal at the cylinder head and such pumps are subject to leakage which considerably reduces their efliciency and requires the use of pumps of extra capacity to perform certain pumping operations.

It is an object of this invention to construct and to assemble the operating parts of a pump in such a manner that a tight seal will result. Another object ofthis invention is to construct a cylinder head afid'liner for a pump so that they may be employed and removed as a unit. Another object of the invention is to simplify the cylinder head construction of pumps which are particularly adapted to the reduction of pressure. Other objects of the invention will be in part apparent and in part set forth as the description proceeds.

The figure of the drawing is a vertical section through a pump of a type in which this invention is applicable, some of the parts being diagrammatically shown.

In the drawing the numeral refers generally to a housing, only the upper portion of which is shown. The housing may conveniently be a casting of iron or steel having a cylinder 11 which is provided with an internal seat 14 which is designed to receive a cylinder liner 50. The cylinder is enlarged at its upper end 12 to provide screw-threaded mountings 13 for bolts 15 and is interiorly reduced at 16 to provide a chamber 17 which extends to and is terminated by a bulkhead 18. The chamber 17 is annular. The bulkhead 18 is extended upwardly at 19 to form a bearing for the connecting rod 20 which is mounted therein for reciprocating motion. Mounted by means of screw-threads 22 upon the upper end of the connecting rod 20, is the piston head 21. The piston in this pump is out of contact with the liner '50 and sealing of the operating surface thereof is accomplished by an annular metallic bellows 23 which is attached at its upper end to a skirt 24 of the piston, and at its lower end to a ring 25, which is mounted on the lower end of the liner 50. The mere use of the bellows seal which has just been described, is not a part of this invention. It is in the cylinder head and liner construction, and the combination thereof as a part of the pump, that this invention lies.

The liner 50 has a seat 51 conforming to the seat 14 of the cylinder. Above the seat 14 the upper outer part of the liner has formed upon the surface thereof an annular flange 52, the lower face of which forms a ledge 53 which rests upon the upper face of the part 12 of the cylinder. The upper face 54 of the annular flange '52 forms a ledge adapted to receive the flange 55 of a clamping ring 56. A small flange 57 projects downwardly from the ring 56 and serves as a fulcrum which enables the bolts 15 to apply leverage to the flange 5S and the seat 54 so that the liner 50 when so held willbe true with respect to'tlie center line of the piston. This application of leverage is to-some extent accomplished through the resilience of the metal of which the clamping ring 56 is made. The upper inner surface 58 of the liner is reduced to form a ledge 59, the face of which is upwardly directed, and is designed 'to receive a similar ledge upon the periphery er the cylinder head30. The cylinder head 30 has an inlet pipe 31 which communicates through a passage 32 and a reed valve 33 with the interior of thepiston so that upon the down strokeof the .piston the pressure "within the pipe 31"will'be reduced as the valve is opened.

Also maintained in the cylinder is a reed valve 34 which communicates with a passage 35 and an outlet pipe 36 so that on the up stroke of the piston the valve 33 will be closed, the valve 34 will be opened, and the contents of the chamber between the top of the piston and the cylinder head will be expelled into the outlet pipe 36. The lower part 37 of the circumference of the annular cylinder head is reduced in order to form the ledge 38 which is designed to rest upon the ledge 59 of the cylinder liner. The inner face of the upper portion of the liner is extended above the end of the cylinder, as shown in the drawings, and its inner face conforms to the outer circumferential face of the cylinder head. The upper end 60 of the liner and the upper outer edge 40 of the cylinder head extend as fine flanges which are joined by an atomic weld so that the cylinder liner and the cylinder head become, in effect, integrated and can be mounted and removed as a unit.

The structure which has just been described is susceptible of fine machining so that clearances of .002 inch between the liner, the piston, and the cylinder head are feasible, although clearances of .004 are generally satisfactory for ordinary work. The sealing which is obtained by this method of construction is, when the structure is carefully assembled, absolute so far as testing apparatus is capable of showing, and leaks less than .0018 micron of mercury per cubic foot per day at a pressure differential of one atmosphere under ordinary conditions of construction. The details of construction, of conforming shapes, and of the leverage that is applicable to the parts in assembled relation by reason of the construction all contribute to the efliciency of sealing. A particular advantage of the invention arises from the considerable simplicity and smaller number of parts used in the construction, compared with structures of the prior art.

Since many embodiments might be made of the present invention and since many changes might be made in the embodiment described, it is to be understood that the foregoing description is to be interpreted as illustrative only and not in a limited sense.

I claim:

1. A cylinder liner assembly comprising a cylinder having an annular end and an internal seat for a liner, a cylinder liner having a conforming seat and a circumscribing flange with upper and lower faces of which the lower forms a ledge for seating the liner upon the cylinder end and the upper forms a ledge for the reception of a clamping ring, a clamping ring having a flange to engage the upper ledge of the liner flange and a flange to bear upon the end of the cylinder, means to clamp the ring and the liner in place comprising bolts seated in the cylinder end, an annular ledge within the liner having an upwardly directed face, a cylinder head conforming to the inner cir- 3 cumference of the liner and having a ledge with a downwardly directed face abutting the annular ledge on the liner, and means to unite the liner and head comprising abutting fine flanges sealed by atomic welding.

2. A cylinder liner assembly comprising a cylinder. having an annular end and an internal seat for a liner, a cylinder liner having a conforming seat and a circumscribing flange with upper and lower faces of which the lower forms a ledge for seating the liner upon the cylinder end and the upper forms a ledge for the reception of a clamping ring, a clamping ring having a flange to engage the upper ledge of the liner flange and a flange to bear upon the end of the cylinder, means to clamp the ring and the liner in place comprising bolts seated in the cylinder end, an annular ledge within the liner having an upwardly directed face, a cylinder head conforming to the inner circumference of the liner and having a ledge with a downwardly directed face abutting the annular ledge on the liner, and means to integrate and to unite liner and head.

3. A cylinder liner assembly comprising a cylinder having an internal seat for a liner, a cylinder liner having a conforming seat and a circumscribing flange with upper and lower faces of which the lower forms a ledge for seating the liner upon the cylinder end and the upper forms a ledge for the reception of a clamping ring, a clamping ring engaging the upper ledge of the said circumscribing flange, a ledge within the liner having an upwardly directed face, a cylinder head conforming to the inner circumference of the liner and having a ledge with a downwardly directed face abutting the inner ledge of the liner, and means to integrate and to unite liner and head.

References Cited in the file of this patent UNITED STATES PATENTS 1,088,520 Black Feb. 24, 1914 1,227,240 Bie May 22, 1917 1,245,451 Fornaca Nov. 6, 1917 1,525,647 Haughey Feb. 10, 1925 1,559,284 Schmid et al. Oct. 27, 1925 1,632,262 Aikmau June 14, 1927 1,768,799 Stanley July 1, 1930 1,940,677 Dymock Dec. 26, 1933 

